This invention relates to high current welding electrodes and more particularly relates to a versatile continuous welding electrode which is usable for short circuit welding a work piece located in any position.
An elongated continuous consumable welding electrode is used in electrical arc welding. The consumable welding electrode consists of a continuous metal core having a welding flux material coated on its outer surface; and circumscribing gaps are formed on the flux coating at regular intervals to expose the metal core such that high welding current may be provided to the electrode through these exposed gaps for the welding operation without any resistance loss of the welding current. In an electric arc welding operation, a welding current density of about 20 amperes per square millimeters is used to provide an electric arc when the tip of the electrode is placed at a close proximity to the weld area of the work piece. The electric arc causes the weld area of the work piece, the metal core as well as the welding flux to melt; and the slag of melted mixture of the metal core and flux is ejected onto the weld area. The slag subsequently solidifies to form the weld metal at the weld area. In order to prevent the melted mixture of metal core and flux material from ejecting outside of the weld area, an insert gas or a physical shield is commonly provided around the weld area. The shield prevents the ejecting mixture from depositing outside of the weld area. Such shielding arrangement increases the complexity of the welding gun and renders it difficult to operate. Furthermore, it is difficult and sometimes impossible to carry out welding on a work piece which is located in a vertical position or in an overhead position due to that the ejecting molten welding mixture would fall away from the work piece due to gravity.
Another problem in using the consumable continuous welding electrode with a welding gun is that the welding operation may be disrupted when the distance between the current application gap and the tip of the electrode is less than a certain length, typically less than 2.6 cm. Under this condition, a short circuit would occur to cause the termination of the welding arc and thus the abrupt termination of the welding operation.
The present invention provides a continuous welding electrode which facilitates continuous welding operation under short circuit condition. The welding operation may be carried out without shielding and with the direct contact of the welding tip to the work piece. The welding slag is formed directly on the weld area. Thus, welding may be carried out on a work piece which is located in any position including in the vertical position or at a directly overhead position. Furthermore, the welding material would penetrate deeply into the joint at the weld area of the work piece to provide an extremely strong bond. The electrode is suitable for use with a continuous welding gun such that shown in U.S. Pat. No. 5,603,855 to Chong Yang Ni.
It is a principal object of the present invention to provide a consumable continuous welding electrode which is suitable for short circuit welding operation.
It is another object of the present invention to provide a continuous welding electrode which facilitates welding without shield and the production of welding arc.
It is another object of the present invention to provide a continuous welding electrode is suitable for use with a continuous welding gun.
It is yet another object of the present invention to provide a continuous welding electrode which facilitates formation of welding slag penetrating deeply into the joint of the work piece.